Thin-film photoelectric converters such as solar cells are manufactured, for example, by depositing a transparent electroconductive oxide layer such as zinc oxide, at least one photoelectric conversion layer, and a back electrode made of a metallic material in this order on a transparent substrate such as glass.
The use of a zinc oxide (ZnO) film as a transparent electroconductive oxide layer has been recently studied strenuously. This film excels a tin oxide (SnO2) film in chemical stability such as resistance to plasma and is kept from degradation in film-formation of a photoelectric conversion layer by means of a plasma CVD method. There is a need for a transparent electroconductive oxide layer, which lets light pass through into a photoelectric conversion layer and functions as a transparent electrode, to have a high light transmittance and a high electroconductivity.
In order to achieve such a high electroconductivity, for example, a patent document 1 specified below discloses a technique to balance a transmittance and an electroconductivity by involving two kinds of impurities in a transparent electroconductive oxide layer so as to diminish a total amount of impurities so that a high light transmittance and a high electroconductivity of the transparent electroconductive oxide layer are achieved.
Patent Document 1: JP 2001-7026 A